2. VoIP - Voice over Internet Protocol

2.1 What makes VoIP fundamentally different to traditional telephones?

The old telephone system uses the POTS system (Plain Old Telephone Service) is an analog switching system that creates and end to end connection between 2 phones. It is a bidirectional system so the signal can be sent both ways at the same time. The POTS system was created purely for voice then faxing and other services were added. The signal is unmodified from start to finish and there are no needs for data integrity because the signal has a dedicated line.

VoIP (Voice over Internet Protocol) uses the Internet to send packets of data. Because the internet is a large network of potentially congested links there are a few protocols that are in place to keep the data from going astray.

First off the data is converted, compressed and encrypted from an analog signal to a digital packet. This digital packet is then split up into many packets and time stamped to identify what order the packets have to be received in. these packets are then sent over the internet to their destination and received, reordered and converted back to an analog signal.

2.2 What are three advantages of VoIP?

a) VoIP is far more cost effective than POTS because you can use and existing technology to communicate with and use freely if used in the right situations. For businesses to be able to have many phone connections over one internet connection is and instant saving let alone cheaper calls and free calls within the organisation.

b) Voice and video can be included in the same data packet with VoIP.

c) You can make conference calls to many people at the same time.

2.3 What are three disadvantages of VoIP?

a) Congested internetworks can cause loss of quality for the service because data packets can get lost or take too long to get to the destination.

b) A fast internet connection is required to use voice transmission over the internet. A lot of the world still can get a fast enough internet connection so VoIP is restricted because of infrastructure of the telecommunications companies.

c) The outlay cost for setting up VoIP for an individual can be great. POTS is in every house and ready to use strait away. VoIP requires special converting boxes or phones, a fast internet connection and maybe even a pc. If the individual doesn’t have and of these in place, the outlay to get VoIP can out weigh the cost of using the POTS system for many years.

2.4 Give three examples of VoIP technology and explain how they are different.

a) Instant Messengers are free programs that can be used with each other to communicate with. First you need a pc. A microphone, speakers and an internet connection but after that using MSN or Yahoo is free.

b) With a small fee, programs like Skype can be used to communicate with other people over the internet then converted to a POTS system so you can call them on the normal telephone system.

c) A one-to-many system can be used too. Programs like Ventrillo and Teamspeak can be used to allow many people to join the same channel and with a press of the button one person can say something and everyone that that’s in the same channel will be able to hear what they have to say.

2.5 (CR) Do you think that one day all telephony will be based on VoIP? Why?

I think all communication will be based on the VoIP because it is a Protocol that’s freely available to use and it uses an infrastructure that is already in place (Internet). It will be a long time before it will be the dominant way of communicating. It offers so many benefits that there is no reason for it to fail. Its far more cost effective than POTS, one cable can carry many calls where as you need an individual cable for each connection with the POTS system and because the internet is constantly growing and expanding VoIP only has to wait before its time.

The only thing slowing it down is the costly outlay for most individuals but for a business, there is no reason why not to convert to it.

2.6 VoIP Sources